A SpaceX Falcon 9 lifted off from Vandenberg Space Force Base in California at 12:39 a.m. PDT on October 10, 2026, carrying 21 data-transport satellites for the Space Development Agency (SDA). The mission, designated Tranche 1 Transport Layer A (T1TL-A), followed an automatic countdown abort five days earlier.
The T1TL-A mission carried 21 SDA satellites
The 21 satellites were part of the SDA’s Proliferated Warfighter Space Architecture (PWSA), a planned low Earth orbit network intended to support military tactical communications, missile warning and tracking. The mission advanced the planned Tranche 1 buildout; its launch did not itself establish the network’s intended operational performance.
The SDA’s planned Tranche 1 includes 126 Transport Layer satellites and 28 Tracking Layer satellites, plus four additional missile-defense demonstration spacecraft. The broader Transport Layer plan calls for 300–500 satellites at altitudes of 750–1,200 kilometers, with a goal of having at least two T1TL satellites in view across 95% of the globe.
The October 5 countdown stopped with 58 seconds remaining
The first T1TL-A launch attempt, on October 5, ended when the countdown was automatically aborted with 58 seconds left. Falcon 9 lifted off on October 10. No specific engineering cause is needed to describe the sequence: the countdown stopped, and the mission flew five days later.
Booster B1103 landed at Landing Zone 4
Falcon 9’s first-stage booster, B1103, landed at Landing Zone 4 about 7.5 minutes after liftoff. It was the booster’s sixth flight. The webcast covers the ascent and first-stage recovery.
Where T1TL-A fits in the SDA’s planned network
T1TL-A was the fourth of nine SpaceX launches planned to help assemble Tranche 1. The wider PWSA concept uses optically connected satellites in low Earth orbit to relay military communications and support missile warning and tracking. Those are goals for the planned network, not outcomes established by this individual flight.
